Needmoremoney
TYF Newbie
1999 denali, 5.7L 150k mileage....was having P0300 code issue some months back, cap & rotor resolved it. Shortly thereafter, P0303 popped up. I have driven the truck on a few vacations, ranging from 400 miles to 1200 miles round trip since this issue started. Cylinder 3 has anti-fouling extension on plug-which seems to help. If i wire brush the plugs, and the extension, then erase the code, i can USUALLY get 100 to 500+ miles before the SES lite comes on. Even after it does, i can USUALLY get ANOTHER 100-500 miles before the miss is noticeable...then i repeat. I KNOW, i should either pay the $ to fix it, or replace the vehicle, but, it just keeps going so why throw out the cow if the milk goes sour .
So a week ago there was a pretty hefty miss especially going up hill. In addition to the P0303, it also threw P1870 & P0155. I checked fluid & tranny was for some reason 1-1/2 qts low. Added it, cleaned plugs, erased codes & got 200 trouble free miles before the SES lite came on today. Tranny code gone, P0303 of course came back, P0155 again & now it added P0171.
Regarding the P0171, tomorrow i will try the 3 easiest things-check intake manifold bolts, clean MAF sensor (air filter replaced in may), & change fuel filter....which has not been changed in....TOO MANY miles (20k maybe).
So a couple questions here:
*are they related, or 3 different issues?
*everything i see online says 'do THIS....if BOTH 0171 AND 0174 throw....'-but i see nothing for ONLY 0171. Wouldn't a dirty MAF sensor, clogged fuel filter, bad fuel pump, regulator, etc throw BOTH 0171 & 0174 ? Or not always? For JUST left bank, 0171, anything in particular i should check, or am i going right direction?
So a week ago there was a pretty hefty miss especially going up hill. In addition to the P0303, it also threw P1870 & P0155. I checked fluid & tranny was for some reason 1-1/2 qts low. Added it, cleaned plugs, erased codes & got 200 trouble free miles before the SES lite came on today. Tranny code gone, P0303 of course came back, P0155 again & now it added P0171.
Regarding the P0171, tomorrow i will try the 3 easiest things-check intake manifold bolts, clean MAF sensor (air filter replaced in may), & change fuel filter....which has not been changed in....TOO MANY miles (20k maybe).
So a couple questions here:
*are they related, or 3 different issues?
*everything i see online says 'do THIS....if BOTH 0171 AND 0174 throw....'-but i see nothing for ONLY 0171. Wouldn't a dirty MAF sensor, clogged fuel filter, bad fuel pump, regulator, etc throw BOTH 0171 & 0174 ? Or not always? For JUST left bank, 0171, anything in particular i should check, or am i going right direction?
